Multiple conductor electrical cables, such as telephone cables, typically include bundles of insulated wire conductors contained within a weather resistant outer sheath of lead, plastic or other protective materials. These cables are often buried under ground or mounted on supports above ground. To minimize deleterious electrical effects of insidious moisture leaks, it is now common practice to maintain a positive gas pressure, such as by air or nitrogen, to prevent inward leaks of moisture. While such gas pressurization is desirable in controlling moisture, problems arise in maintenance, repair and in making splices or connections of other cables thereto. In making a repair, for example, of a damaged outer sheath, or in splicing, it is often necessary to remove a portion of the sheath, exposing thereby the interiorly contained conductors. Upon sealing such exposed cables, it is then necessary, using currently available techniques, to totally depressurize the cable to effectively apply sealant products. Without such depressurization, the gas escaping from the exposed cable causes air pockets and bubbles in the sealant products, effectively preventing the achievement of a reliable cable sheath seal. Accordingly, to enable proper sealing, known current practices require the gas pressure to be turned off. Such depressurization and then repressurization can typically take several hours resulting in not only wasted time and additional costs, but also in an increase in the potential for moisture leaks during the depressurization period.